Deduplicate raw TextContent fallback in tool result conversion

[Copilot]

internal/mcp/tool_result.go repeated the same marshal-to-TextContent fallback in four branches of ConvertToCallToolResult / convertMapToCallToolResult. This change centralizes that behavior so fallback handling stays consistent as the conversion logic evolves.

• Refactor fallback construction

  • Extract marshalValueToTextContentResult to own the shared:
    • json.Marshal(...)
    • sdk.CallToolResult{Content: []sdk.Content{&sdk.TextContent{...}}}
    • error wrapping on marshal failure
  • Replace the four duplicated fallback blocks with calls to the helper

• Behavior preserved across existing fallback paths

  • direct array input ([]interface{})
  • scalar / non-structured input
  • map input with missing or nil content
  • map input with unrecognized content shape

• Focused coverage

  • Add a unit test for the content: nil map case to ensure it still falls back to raw text wrapping

func marshalValueToTextContentResult(value interface{}) (*sdk.CallToolResult, error) {
	dataBytes, err := json.Marshal(value)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal backend result: %w", err)
	}
	return &sdk.CallToolResult{
		Content: []sdk.Content{&sdk.TextContent{Text: string(dataBytes)}},
	}, nil
}

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  • Triggering command: /tmp/go-build2637788630/b513/launcher.test /tmp/go-build2637788630/b513/launcher.test -test.testlogfile=/tmp/go-build2637788630/b513/testlog.txt -test.paniconexit0 -test.timeout=10m0s .o .o .o .o .o .o f07e34dca1.build--exclude-standard lib/rustlib/x86_--others lib/�� lib/rustlib/x86_64-REDACTED-linux-gnu/lib/libobject-926daa94a00ee327.rlib lib/rustlib/x86_64-REDACTED-linux-gnu/lib/libmemchr-48d5b0db80402653.rlib lib/rustlib/x86_64-REDACTED-linux-gnu/lib/libaddr2line-3367f26bd486b29d.rlib (compatibility issue with Go 1.25.0). Continuing with other checks..."; \ elif command -v golan lib/rustlib/x86_--norc lib/rustlib/x86_--noprofile 05ed-cgu.00.rcgu.o (dns block)
• this-host-does-not-exist-12345.com
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[Copilot]

Pull request overview

Refactors internal/mcp/tool_result.go to centralize the “marshal backend value and wrap as a single TextContent” fallback used by ConvertToCallToolResult and convertMapToCallToolResult, keeping fallback behavior consistent while reducing duplication.

Changes:

• Extracts repeated marshal-and-wrap fallback into marshalValueToTextContentResult.
• Replaces four duplicated fallback blocks with the helper.
• Adds a unit test covering the map[string]interface{}{ "content": nil, ... } fallback case.

Show a summary per file

File	Description
internal/mcp/tool_result.go	Introduces marshalValueToTextContentResult and routes existing fallback branches through it.
internal/mcp/tool_result_test.go	Adds coverage for the content: nil map fallback behavior.

Copilot's findings

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• Files reviewed: 2/2 changed files
• Comments generated: 0